Hydraulic clamp bushing having sigma shaped bushing ends

Abstract

Hydraulic clamp bushing (13, 14) having a double walled sleeve (7), a hydraulic pressure medium which is trapped in a chamber (5) between the sleeve walls, and a mechanism for pressurizing the pressure medium. One, or both, sleeve walls (7) is/are formed for expanding radially outwards and/or inwards when the pressure medium is pressurized, whereby the clamp bushing is clamped to a shaft, a hub or a similar object, in particular a rotary shaft (17, 18). The pressure medium chamber (5) is formed with angularly inwards or sigma formed bushing ends (9) designed so that the ends are straightened up as a first stage when the clamp bushing is pressurized, whereby the axial ends of the bushing facing the shaft (17, 18) are pressed to the shaft (17,18) thereby providing a straightening up of the bushing (13, 14) on the shaft before the intermediate portions of the sleeve are pressed to the shaft (17, 18).

I claim: 
     
       1. A hydraulic clamp bushing which is connectable to a rotary shaft for transmitting axial or rotary torques, said clamp bushing comprising: a closed circular sleeve having two sleeve walls and two bushing ends, at least one of said sleeve walls being formed as an expandable sleeve wall so as to expand radially outwards or inwards;   a pressure medium chamber between said two sleeve walls having a hydraulic pressure medium trapped therein;   a pressurizing means for pressurizing said hydraulic pressure medium to cause said expandable sleeve wall to expand radially outwards or inwards when said pressurizing medium is pressurized whereby the clamp bushing is adapted to be clamped to the rotary shaft;   wherein said two bushing ends of said closed sleeve are shaped with a respective inwardly directed fold prior to pressurizing of said pressure medium, and said inward folds of said bushing ends are then straightened when said pressure medium is pressurized; and   wherein said expandable sleeve wall has respective end parts at and adjacent respective said bushing ends and intermediate parts between said end parts, said end parts having a thickness of material which is less than a thickness of material of said intermediate parts whereby respective axial end edges at an intersection of said expandable sleeve and said respective bushing ends are adapted to be initially pressed against the rotary shaft as said pressure medium is first pressurized by said pressurizing means in order to straighten up the clamp bushing relative to the rotary shaft before said intermediate wall parts are pressed to the rotary shaft by said pressure medium.   
     
     
       2. A clamp bushing as claimed in claim 1, wherein the bushing ends are folded angularly inwards into a sigma (Σ) shape having straight legs. 
     
     
       3. A clamp bushing as claimed in claim 2, wherein the bushing ends are angularly formed to such extent that the straight legs thereof provide an angle to each other of 70°-110°. 
     
     
       4. A clamp bushing as claimed in claim 3 wherein the angle of said straight legs is about 90°. 
     
     
       5. A clamp bushing as claimed in claim 1, wherein a length of contact of the expandable sleeve wall between said bushing ends is substantially the same as a total length of the clamp bushing, whereby the clamp bushing is adapted with the entire length thereof to engage the rotary shaft when said pressure medium is fully pressurized. 
     
     
       6. A clamp bushing as claimed in claim 1, wherein the expandable sleeve wall is formed with successively changed thickness of material along a length of the expandable sleeve wall. 
     
     
       7. A clamp bushing as claimed in claim 1, wherein the expandable sleeve wall is formed with stepwise changed thickness of material along a length of the expandable sleeve wall.